Survival of patients with multiple primary malignancies: a study of 783 patients with gastrointestinal stromal tumor

Abstract

Background: We sought to investigate the characteristics and survival rate of patients with gastrointestinal stromal tumor (GIST) associated with other primary malignancies.

Patients and methods: A total of 783 patients with GIST were identified from 1995 to 2007. Additional primaries included tumors not considered metastasis, invasion, or recurrence of GIST, nor non-melanoma skin cancer. Data on gender, age at diagnosis, follow-up time after diagnosis, and death were collected.

Results: Of the 783 patients with GIST, 153(20%) were identified with at least one additional primary. Patients with additional primaries were more often men (M : F 1.5 versus 1.3) and older (66 versus 53 years). More patients had another cancer diagnosed before (134) than after (52) GIST. Primaries observed before GIST were cancers of the prostate (25), breast (12), esophagus (9), and kidney (7) and melanoma (6). Lung (5) and kidney (5) primaries were the most frequent after GIST. The 5-year survival was 68% for patients with primaries before GIST, 61% for patients with primaries after GIST, 58% for patients with GIST only, and 49% for patients with two or more primaries in addition to GIST (P = 0.002).

Conclusions: Approximately 20% of patients with GIST develop other cancers. Inferior median 5-year survival was observed in patients with GIST with two or more other cancers. The etiology and clinical implications of other malignancies in patients with GIST should be investigated.

Figure 1.

Histological subtype of additional malignancies in patients with GIST. Percentages represent the proportion of patients with additional malignancies. GI, gastrointestinal; GIST, gastrointestinal stromal tumor; GU, genitourinary.

Figure 2.

Survival probability by additional malignancy grouping. Patients with GIST alone appeared to have a trend toward the best overall survival (group III). Patients with GIST and two or more cancers were found to have a statistically significant inferior overall survival (P = 0.007). Patients with GIST as the first malignancy and a subsequent tumor (group I) and patients with another malignancy in their history (group II) had an intermediate survival compared with groups III and IV. GIST, gastrointestinal stromal tumor.